1. Field of the Invention
The present invention relates to high voltage fuse construction, and more particularly to support assemblies for supporting fusible elements in high voltage fuses.
2. Description of the Prior Art
High voltage current limiting fuses are well known to the art. Prior art current limiting fuses typically comprise a hollow insulated cylindrical housing which is closed at both ends by metallic end walls. A helically wound fusible element is positioned within the housing and is connected to the end walls. The current limiting fuses are typically filed with an electrically non-conducting insulating material such as silica or quartz sand which surrounds the fusible element. Since it is necessary to assume that the fusible element maintains the proper distance from the sides of the insulated housing and that the individual turns of the fusible element are maintained at a uniform distance to assure that there is no arcing between the turns, prior art current limiting fuses have typically included a support assembly for supporting the fusible element within the fuse housing.
Difficulty has been experienced in prior art current limiting fuse constructions in terminating the fusible element. Twisting or distortion of the fusible element at the point of connection within the fuse can result in arcing between turns or damage to the fusible element. Further, since the fusible element is typically fabricated from a silver material, electrical connection of the fusible element by welding can result in damage to the fusible element unless the welding temperatures are held to a relatively low level. Thus, it would be a desirable advance in the art to provide a means of terminating the fusible element that eliminates distortion of the fusible element and facilitates welding of the fusible element.
In addition, since cost is always a factor for any commercial item, it is desirable to provide a current limiting fuse construction that minimizes the number of dissimilar parts and facilitates rapid, low labor cost assembly. Accordingly, it would be a desirable advance in the art to provide a support assembly for a current limiting fuse that reduces the number of dissimilar parts, reduces the labor expense in construction, and maximizes the amount of sand filler material surrounding the fusible element. In addition, it is desirable to assure that the fusible element will be arranged and retained in such a position that the proper concentric alignment of the fusible element with respect to the walls of the current limiting fuse is maintained to prevent localized overheating the walls.